The lack of adequate transportation infrastructure in Brazil has been a bottleneck for the soybean producers for many years. Moreover, the costly inland transportation incurred from this bottleneck has resulted in a loss in competitiveness for Brazil compared to other exporting countries, especially the United States. If transportation costs are reduced by introducing improved infrastructure, Brazil is expected to increase its competitiveness in the world soybean market by increasing its exports and producer revenues. On the other hand, the United States and other significant soybean competing exporting countries are expected to lose market share as well as producer revenues. This study uses a spatial equilibrium model to analyze transportation infrastructure improvements proposed by the Brazilian government vis-à-vis enhance the nation’s soybean transportation network. The analyzed transportation improvements are: (i) the development of the Tapajós-Teles Pires waterway; (ii) the completion of the BR- 163 highway; (iii) the construction of the Mortes-Araguaia waterway; (iv) the Ferronorte railroad expansion to Rondonópolis and the linkage between the city of Rio Verde to Uberlândia; and (v) the Ferropar railroad expansion to the city of Dourados. The model specifies the Brazilian inland transportation network and the international ocean shipments. The model divides Brazil into 18 excess supply regions and 8 excess demand regions. The competing exporting countries are the United States, Argentina, Rest of South America (Bolivia, Paraguay, and Uruguay), Canada, and India. The importing countries are composed of China, European Union, Southeast Asia, Mexico, and the Rest of the World. Results suggest these proposed transportation improvements yield potential noteworthy gains to Brazil with producer revenues increasing more than $500 million and exports increasing by 177 thousand metric tons. Consequently, the world soybean price declines by $1.16 per metric ton and producer revenues and exports in the United States fall by 63 thousand metric tons and $104.89 million, respectively. Although the absolute gains in price, revenues, and exports for Brazil are considerable, they only represent in relative changes 1.48, 2.35, and 0.32 percent, respectively. Similarly, the loss in price, revenue, and export value for the United States is also low, declining by 0.23, 0.23, and 0.12 percent, respectively.

The lack of adequate transportation infrastructure in Brazil has been a bottleneck for the soybean producers for many years. Moreover, the costly inland transportation incurred from this bottleneck has resulted in a loss in competitiveness for Brazil compared to other exporting countries, especially the United States. If transportation costs are reduced by introducing improved infrastructure, Brazil is expected to increase its competitiveness in the world soybean market by increasing its exports and producer revenues. On the other hand, the United States and other significant soybean competing exporting countries are expected to lose market share as well as producer revenues. This study uses a spatial equilibrium model to analyze transportation infrastructure improvements proposed by the Brazilian government vis-à-vis enhance the nation's soybean transportation network. The analyzed transportation improvements are: (i) the development of the Tapajós-Teles Pires waterway; (ii) the completion of the BR- 163 highway; (iii) the construction of the Mortes-Araguaia waterway; (iv) the Ferronorte railroad expansion to Rondonópolis and the linkage between the city of Rio Verde to Uberlândia; and (v) the Ferropar railroad expansion to the city of Dourados. The model specifies the Brazilian inland transportation network and the international ocean shipments. The model divides Brazil into 18 excess supply regions and 8 excess demand regions. The competing exporting countries are the United States, Argentina, Rest of South America (Bolivia, Paraguay, and Uruguay), Canada, and India. The importing countries are composed of China, European Union, Southeast Asia, Mexico, and the Rest of the World. Results suggest these proposed transportation improvements yield potential noteworthy gains to Brazil with producer revenues increasing more than $500 million and exports increasing by 177 thousand metric tons. Consequently, the world soybean price declines by $1.16 per metric ton and producer revenues and exports in the United States fall by 63 thousand metric tons and $104.89 million, respectively. Although the absolute gains in price, revenues, and exports for Brazil are considerable, they only represent in relative changes 1.48, 2.35, and 0.32 percent, respectively. Similarly, the loss in price, revenue, and export value for the United States is also low, declining by 0.23, 0.23, and 0.12 percent, respectively.

The Classical Model describing the effects of temperature on enzyme activity consists of two processes: the catalytic reaction defined by ΔG cat and irreversible inactivation defined by ΔG inact, this model however, does not account for the observed temperature- dependant behaviour of enzymes. The recent development of the Equilibrium Model is governed not only by ΔG cat and ΔG inact but also by two new intrinsic parameters ΔHeq and Teq, which describe the enthalpy and the temperature of the midpoint, respectively, of a active and reversibly inactive enzyme transition. Teq is central to the physiological adaptation of an enzyme to its environmental temperature and links the molecular, physiological and environmental aspects of life to temperature in a way that has not been previously possible. The Equilibrium Model is therefore a more complete and accurate description of the effects of temperature on enzymes, it has provided new tools for describing and investigating enzyme thermal adaptation and possibly new biotechnological tools. The effects of the incorporating in the new Model of the parameters Teq and ΔH eq yield major differences from the Classical Model, with simulated data calculated according to the Equilibrium Model fitting well to experimental data and showing an initial rate temperature optimum that is independent of assay duration. Simulated data simulated according to the Classical Model can not be fitted to experimental data. All enzymes so far studied (gt30) display behaviour predicted by the Equilibrium Model. The research described here has set out to: experimentally test observations made by Eisenthal et al., on the basis of enzyme reactor data simulated according to the Equilibrium Model; to test the Equilibrium Model using an unusual (rapidly renaturable) enzyme, RNAase; and to test the proposed molecular basis of the Equilibrium Model by examining the effect of a change at the enzymes active site. The experimental results gathered here on the effect of time and temperature on enzyme reactor output confirm the predictions made by Eisenthal et al. (2006) and indicate that the Equilibrium Model can be a useful aid in predicting reactor performance. The Equilibrium Model depends upon the acquisition of data on the variation of the Vmax of an enzyme with time and temperature, and the non-ideal behaviour of RNase A made it impossible to collect such data for this enzyme, as a result the Equilibrium Model could not be applied. The disulfide bond within the active site cleft of A.k 1 protease was cleaved as a probe of the mechanism of the Equilibrium Model, which is proposed to arise from molecular changes at the enzymes active site. Support for the proposed mechanism was gained through the comparison of experimentally determined temperature dependence of the native and reduced forms of the enzyme and application of this data to the Equilibrium Model.

In this paper, we study the asset pricing implication of imprecise knowledge about rare events. Modeling rare events as jumps in the aggregate endowment, we explicitly solve the equilibrium asset prices in a pure-exchange economy with a representative agent who is averse not only to risk but also to model uncertainty with respect to rare events. Our results show that there are three components in the equity premium: the diffusive-risk premium, the jump-risk premium, and the "rare event premium." While the first two premia are generated by risk aversion, the last one is driven exclusively by uncertainty aversion. To dis-entangle the "rare event premium" from the standard risk-based premia, we examine the equilibrium prices of options with varying degree of moneyness. We consider models with different levels of uncertainty aversion -- including the one with zero uncertainty aversion, and calibrate all models to the same level of equity premium. Although observationally equivalent with respect to the equity market, these models provide distinctly different predictions on the option market. Without incorporating uncertainty aversion, the standard model cannot explain the extent of the premia implicit in options, particularly the prevalent "smirk" patterns documented in the index options market. In contrast, the models incorporating uncertainty aversion can generate significant premia for at-the-money option prices, as well as pronounced "smirk" patterns for options with different degrees of moneyness.

<p> The growth kinetics of a plates and rods in B-brass have been calculated using a local equilibrium model. These are in good agreement with published experimental data. Along with this, quantitative microanalysis of deep etched specimens ts cited in support of the proposed diffusional mechanism for their formation. </p> <p> The model was also employed to calculated the growth rates of upper bainitic rods in the Fe-C-Nisystem at 400° C. A "phase diagram" was constructed in order to supply the effective supersaturations required by the local equilibrium model$ Lengthening rates were also calculated using a paraequilibrtum Interface condition. The experimental data were correctly predicted assuming the former case but failed at the "phase" boundary. It seems that a solute drag might well operate in this system. These results have provided some further indication of the part alloying elements play in the formation of the microstructural constituents of steel. </p> / Thesis / Master of Engineering (MEngr)

The recently proposed and experimentally validated Equilibrium Model provides the most detailed description of temperature's effect on enzyme catalytic activity to date. By introducing an equilibrium between Eact, the active form of enzyme, and Einact, a reversibly inactivated form of enzyme, the Equilibrium Model explains apparent enzyme activity loss at high temperatures that cannot be accounted for by irreversible thermal denaturation. The Equilibrium Model describes enzyme behavior in the presence of substrates and under assay conditions; thus its associated parameters, deltaHeq and Teq, may have physiological significance. The Equilibrium Model parameters have been determined for twenty-one enzymes of diverse origins. The results demonstrated the wide applicability of the Equilibrium Model to enzymes of different types and temperature affinity. The study has also established deltaHeq as the first quantitative measure of enzyme eurythermalism and demonstrated the relationship between Teq and optimal growth temperature of organisms. The Equilibrium Model is therefore a useful tool for studying enzyme temperature adaptation and its role in adaptations to thermophily and eurythermalism. Moreover, it potentially enables a description of the originating environment from the properties of the enzymes. The Equilibrium Model has been employed to characterize enzymes isolated from bacterial episymbionts of Alvinella pompejana. A. pompejana inhabits one of the most extreme environments known to science and has been proposed as an extremely eurythermal organism. A metagenomic study of the A. pompejana episymbionts has unveiled new information related to the adaptive and metabolic properties of the bacterial consortium; the availability of metagenomic sequences has also enabled targeted retrieval and heterologous expression of A. pompejana episymbiont genes. By inspecting enzymes derived from the unique episymbiotic microbial consortium intimately associated with A. pompejana, the study has shed light on temperature adaptations in this unique symbiotic relationship. The findings suggested that eurythermal enzymes are one of the mechanisms used by the microbial consortium to achieve its adaptations. By combining metagenomic and enzymological studies, the research described in this thesis has lead to insights on the eurythermalism of a complex microbial system from an enzymological aspect. The findings have enhanced our knowledge on how life adapts to extreme environments, and the validation of the Equilibrium Model as a tool for studying enzyme temperature adaptation paves the way for future studies.

Despite the prevalence of computable general equilibrium (CGE) models applied to tax changes of varying types, little work has been done focusing on state level comprehensive tax reform or on tax reform in countries undergoing a regime change. This research develops and applies methodologies for analyzing fiscal policy changes under these two very different economic scenarios. The findings for each application are relevant to policy makers as they weigh the effects of tax reform. The models developed for the two scenarios offer guidance to future modelers in studying similar economies and the contrast of the two provides a framework for thinking about model design and application. Finally, the results, when compared to each other, allow us to see the relative effectiveness of the two tax reform policies given their very different economies.

The base metal distribution in, and losses to, Anglo Platinum six-in-line and slag cleaning furnace slags were characterised to coincide with various process changes at Waterval Smelter from 1999 to 2009. The base metals are presumed to be reliable indicators of PGE losses and are easier to detect and measure than these elements are. In addition, base metal and sulphur levels are used to monitor and control many smelter processes, including slag cleaning and converting. Some losses to slag are recoverable but others are not – these have been quantified during this study. Slag composition and smelting temperatures have varied substantially, and optimisation of the slag cleaning furnace – a first for the South African platinum industry – has produced a wide variation in oxidation conditions. Most of the base metal losses in the slag cleaning furnace are mechanically entrained matte particles, the largest of which should be recovered. These have been examined to establish any relationship between composition, size, and depth within the furnace so that recommendations can be made to limit these types of losses. In the six-in-line furnaces, over half of base metal losses to slag are as dissolved phases, which are not recoverable. Levels of dissolved metals have been measured and related to furnace operating conditions and slag composition. The prediction of such base metal losses is not easy, because the slag compositions are so complex. One aspect of the project has been to compare the measured distribution of the base metals with those calculated using the FactSage equilibrium model, to identify problem areas, and to recommend actions which could improve the predictions of this and similar modelling programs for base metal dissolution in slag. New electron microbeam techniques have been developed to quantify base metal distribution in slag, and novel combinations of these techniques with analytical chemistry and Mössbauer Spectroscopy have been pioneered. / Dissertation (MSc)--University of Pretoria, 2009. / Materials Science and Metallurgical Engineering / unrestricted

Thesis (M.Com. (Economics))--North-West University, Potchefstroom Campus, 2008.

Thesis (M.Com. (Economics))--North-West University, Potchefstroom Campus, 2008.